Shucking of bivalves

ABSTRACT

THIS INVENTION RELATES TO THE METHOD OF AND APPARATUS FIRST SEPARATING THE MEATS OF BIVALVES FROM SHELLS CONTAINING SAME AND COMPRISING A CELL, MEANS FOR CONTINUOUSLY MOVING SAID BIVALVES THROUGH SAID CELL, A HEATING SOURCE DISPOSED ON ONE SIDE OF SAID MOVING MEANS, INTERFERENCE MEANS INTERPOSED BETWEEN SAID SOURCE AND SAID MOVING MEANS FOR RETAINING SAID SOURCE AT A PREDETERMINED DISTANCE FROM SAID BIVALVES, AND MEANS DISPOSED ON THE OPPOSITE SIDE OF SAID MOVING MEANS FOR REGENERATING HEAT SUPPLIED FROM SAID SOURCE WHEREBY SAID BIVALVES ARE COMPLETELY ENVELOPED IN A CONCENTRATED HIGH-TEMPERATURE MEDIUM.   D R A W I N G

' Feb. 23, 1971 H, F. SNQW SHUCKING OF BIVALVES Filed April 8/ 1969 2 Sheets-Sheet l INVI'IN'I'UR. HAROLD F. SNOW ATTORNEY Feb. 23, 1971 H. F. SNOW 3,554,548

SHUCKING OF BIVALVES Filed April a, 71969 2 Sheets-Sheet .2

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HAROLD F. SNOW IiY United States Patent O 3,564,648 SHUCKING OF BIVALVES Harold F. Snow, Scarboro, Maine, assignor to Borden, Inc., New York, N.Y., a corporation of New Jersey Filed Apr. 8, 1969, Ser. No. 814,298 Int. Cl. A22c 29/00 US. Cl. 17-74 9 Claims ABSTRACT OF THE DISCLOSURE This invention relates to the method of and apparatus for separating the meats of bivalves from the shells containing same and comprise a cell, means for continuously moving said bivalves through said cell, a heating source disposed on one side of said moving means, interference means interposed between said source and said moving means for retaining said source at a predetermined distance from said bivalves, and means disposed on the opposite side of said moving means for regenerating heat supplied from said source whereby said bivalves are completely enveloped in a concentrated high-temperature medium.

BACKGROUND OF THE INVENTION Heretofore, a number of patents have been issued covering the complete or partial mechanization of the proces of removing or shucking the uncooked meats of mollusks from their shells.

The most satisfactory method of effecting release nonmechanically of the bonds of the meats to their shells of mollusks, such as clams, oyster, and scallops, is through the use of heat applied to the mollusks either by direct flame impingement or by exposing the mollusks to a very hot gaseous environment having a temperature of 800 F. or higher. Under proper conditions, the bond of the mollusk meats to their shells can be broken, leaving the meat in an entirely raw state whereupon the meat can be dumped out of the shell manually or otherwise. It has always been assumed that a gas flame impinging on a clam must be produced from a burner source located above or beside a clam, since, during the process, clams release salty, sandy juices, and other droppings which would soon foul the orifices of burners located beneath the mollusk. Accordingly, conventional apparatus, including flame sources, were located on either side of a moving single file of clams, each with its mouth pointed upwardly, i.e., the joint defined by the mating rims of the half-shells disposed in a vertical plane. Thus positioned, air, drawn from beneath, passes between the flame and the shell, tending to insulate the latter and thereby obviating or at least materially reducing the bond breakdown. Additionally, the side-mounted flame apparatus requires manual placement and orientation of the clams to insure that the months are vertically positioned.

One of the novel features of the machine herein described is the successful performance of gas burners located directly beneath an open-mesh wireconveyor belt on which the clams are conveyed through the machine. The burners are uniquely designed in such a manner that falling clam juices, sand, and shell debris have no adverse fouling effect whatsoever even after runs of very long duration, whereas any standard burner types tested fouled under these conditions within seconds after the start of the test. In essence, the clams under process are conveyed through a tunnel having a flat roof of heat-resistant material located directly over the clams. This roof is at a sufficient distance from the clams so as to permit ample flue volume for the flow of combustion gases.

SUMMARY OF THE INVENTION The present invention overcomes the stated deficiencies in the prior art of mechanized shucking of bivalves and has as its primary objective the method of and apparatus for concentrating a heat medium, resistant to contamination, which will envelop the bivalve in a controlled environment for a suflicient time to induce complete release of the meat from the containing shell.

More particularly, the invention relates to a foul-proof burner system disposed beneath moving mollusks wherein the air passage beneath the burner upward to the mollusks is preheated to preclude insulation of the shell by cool air between the flame and mollusk surface. Additionally, the invention includes spaced interference rods disposed between the flame nozzle and mollusk which defines the point of ignition of the flame and maintains same at the optimal level for the mollusk-shell bond breakdown. Finally, the invention suggests a refractory layer above the mollusks to reflect heat to the shell upper surface and delimit a concentrated level of controlled heat to effect the bond breakdown sought.

BRIEF DESCRIPTION OF THE DRAWINGS The various features of the apparatus of this invention will become apparent from the following detailed description set forth in connection with the accompanying drawings which relate to the preferred embodiment of the present invention and are given by way of illustration.

FIG. 1 is a top view of the preferred embodiment of the present invention.

FIG. 2 is a longitudinal cross-section view taken along the line II-II of FIG. 1.

FIG. 3 is a transverse cross-section view taken along the line III-III of FIG. 1.

FIG. 4 is a detailed view of the heating environment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION Reference is now made to the preferred embodiment of the present invention which comprises a cell 10 having a top wall 11, preferably disposed in a horizontal plane, having integral vertical endwalls 12 and 13 and sidewalls 14, the latter walls having externally flared skirts 15 to permit passage of air through the open sides. The cell is situated on suitable braces (not shown) to provide an open bottcm.

A bank of cylindrical rollers 17, each secured to a rotatably journaled shaft 18, are disposed in parallel relation within the cell, all in the same horizontal plane. A second bank of cylindrical rollers 19 secured to journal shaft 20 are disposed in a horizontal plane beneath rollers 17. The rollers of both banks are driven in timed rotation by motor means (not shown) such as electric, pneumatic, or internal-combustion engine. A pair of cylinders 21 and 22, secured to driven shafts 23 and 24 respectively, are disposed outside the cell at opposite ends thereof and in the horizontal plane of rollers 17. A foraminous conveyor belt 25, preferably metal, is entrained about the end rollers 21 and 22 and the roller banks which impart movement to the belt to convey the bivalves through the cell. Any conventional feeder apparatus (not shown) may be used to continuously deliver bivalves onto the moving conveyor in a random-spaced arrangement.

A refractory layer 26 comprising a plurality of spaced, heat-reflective planks 27 made of ceramic or the like is disposed above the horizontal conveyor over the length of the cell, to reflect, downwardly, any heat which passes through the belt. The spaces between the planks define ports 28 which permit the escape of exhaust gases. I

A plurality of parallel conduits 29 are disposed beneath conveyor tranverse of the cell and between endwalls 12 and 13 which include, on the upper surface, a number of upwardly projecting nozzles 30. A suitable, flammable gas, such as propane, is supplied, under pressure, to the conduits from a source (not shown) which when ignited, serves as the heating source for the cell.

The spacing the gas nozzles and the conduits which mount the nozzles is carefully controlled to promote a uniform flame without suffocation. More specifically, when the flames are too closely situated, oxygen, which in this embodiment is provided by suction through the open bottom of the cell, is dissipated, and suffocation occurs, extinguishing many of the nozzles. Conversely, too few nozzles or too expansive spacing will not generate sufficient heat to effect complete release of the meat from the shells. In practice, though the embodiment is not to be limited in actual construction or interpretation, the nozzles are spaced approximately an inch and a half apart on each conduit defining a continuous line of gas jets over the length of the cell spaced about 12 inches apart.

The nozzle construction itself is carefully constructed comprising preferably a cylindrical projection extending approximately one-and-three-fourths inches from the conduit with a central bore communicating to the hollow interior of the latter. Though not so limited in the preferred embodiment, the discharge aperture diameter is about 0.07 inch over an axis length of about one-fourth inch with the remaining bore drilled one-eighth inch to reduce gas flow resistance. The outer diameter of the discharge end of the nozzle is reduced to only about three-thirtyseconds of an inch for a distance of about one-fourth inch. The upper face of the nozzle is conical, which assists in the prevention of fouling since debris falling through the belt from the mollusks will not come to rest on the inclined surface. The length of the nozzle from the conduit connection permits substantial residue buildup and encrustration on the surface around the orifice without fouling.

Interposed between the nozzles and the conveyor is a plurality of interference rods 31, one rod parallel to and lying in the same vertical plane as each conduit 26 which locates the vertical point of burning of the flame of the nozzles.

In practice, without interference rods, when gas issuing from the nozzles are ignited, drift occurred, wherein the flame from nozzles on a conduit between two operating conduits tended to move upwardly, even past the foraminous belt. This phenomenon is believed to be due to the upward draft of the air and combustion gases. Consequently, it has been impossible to produce a uniform level of flame for several parallel conduits without using interference rods.

In operation, using the rods, a pilot light ignites the nozzles on each conduit and flame passes upwardly on opposite sides of the rod, providing a uniform bed of flame disposed at a horizontal level beneath the belt. Though not so limited in the preferred embodiment, a metal rod of circular cross-section in the range of one-fourth to threefourths-inch diameter was disposed from about one inch to two-and-one-half inches directly from the nozzle orifices as the interference rod. The nozzle orifices are positioned in a horizontal plane about eight inches beneath the conveyor belt. Gas pressures are generally from about one p.s.i. to three p.s.i. and a regular L. P. gas such as propane is used, rather than premixing the gas with air, to produce a clean flame. The refractory layer 26 regenerates the heat passed through the conveyor so that a concentrated and carefully controlled environment is maintained to completely envelop the bivalves.

The spaced ports 28 communicate with a vacant cavity 32 disposed between the layer and topwall of the cell. A recessed duct 33 situated in the topwall and communicating with the cavity includes an exhaust fan 34 for removal of exhaust gases. The exhaust fan is mounted on a rotatable shaft 35 driven by conventional motor 36.

A pipe 37 extends into the cavity 32 and includes a plurality of nozzles 38 communicable therewith. Water supplied from a source (not shown) is conveyed into the cavity and sprayed through the nozzle 38 to create a fog or mist which facilitates exhaust gas removal for fan 34.

A second continuous conveyor 39 is disposed at a level lower than roller 21 upon which the process bivalves are dumped. Thereafter, the bivalves are conveyed to a controlling environment and the meats are removed manually.

In operation, the linear velocity of the conveyor is controlled so that the maximum time of exposure of the bivalves to the heated environment generally ranges from about forty-five seconds to about three minutes. Each shell is completely enveloped about its circumference face by the concentrated bed of heat achieved by the dispersed flame beneath the belt and the heat radiantly reflected by the refractory layer.

In addition, the upward rush of heat occasioned by the suction of oxygen swirls about the mollusk shell forming eddy currents of heat which are also reflected by the reflective layer 26. Nonetheless, the shells protect the meat against premature cooking.

Although only one embodiment of the present invention has been illustrated and described, it will be evident to those skilled in the art that various modifications may be incorporated into the details of production without departing from the principles herein set forth.

What is claimed is:

1. Apparatus for heating bivalves disposed on a continuously moving means for facilitating separation of the meats from the shells comprising a cell; means for continuously moving the bivalves through the cell; a gas-type heating source disposed on one side of said moving means; and rod-like interference means of relatively small diameter interposed between said heating source and said moving means for preventing drifting of flames upon ignition of flammable gas emanating from said heating source, said interference means presenting a negligible radiating surface and allowing the flames to pass upwardly and around said interference means to form a uniform bed of flame between said interference means and said moving means.

2. Apparatus according to claim -1 wherein said moving means is a foraminous conveyor and said heating source comprises a plurality of flame-producing nozzles beneath said conveyor whereby said interference means prevents drift of the flame to establish a horizontal level of heat.

3. Apparatus according to claim 1 wherein said heating source is disposed below said moving means.

4. Apparatus according to claim 3 including a heat reflecting means disposed above said moving means for diverting the heat against the bivalves lying on said moving means.

5. Apparatus according to claim 4 wherein said reflecting means is a layer of refractory material.

6. Apparatus according to claim 4 wherein said cell includes a ceiling, side walls and end walls, said apparatus further including means for withdrawing exhaust gases from said cell and means for permitting entry of air into said cell to promote proper combustion in the heat source.

7. Apparatus according to claim 6 including means for spraying water in the space between said heat reflecting means and the ceiling of said cell for creating a mist which facilitates removal of exhaust gases from said cell.

8. Apparatus according to claim 6 wherein said side walls include flared skirts for permitting passage of air.

9. Apparatus of claim 3, said heating source including a plurality of spaced parallel conduits disposed transversely to the travel of said moving means, each conduit having a plurality of nozzles for discharging flammable gas; said interference means including a plurality of spaced parallel rods each disposed in parallel fashion a distance above said conduits.

References Cited UNITED STATES PATENTS 10 LUCIE H. LAUDENSLAGER, Primary Examiner US. Cl. X.R. 

